Spread spectrum (SS) systems, such as ultra-wideband (UWB) systems transmit information spread over a large bandwidth. In a UWB system, the source signal is spread over a bandwidth many times larger than its original bandwidth. Pseudo-random or pseudo noise (PN) sequences are periodic sequences with long periods that allow the transmitted signal to have a relatively low signal to noise ratio (SNR). In a direct sequence UWB (DS/UWB) system, the transmitted signal is a train of pulses with polarities determined by the product of a PN binary sequence and the incoming binary source data sequence. For a UWB receiver, the first step of demodulation is to de-spread the signal. In a DS/UWB system, this is achieved by multiplying the incoming samples by a local replica of the PN sequence. The receiver can determine the PN code phase embedded in the transmitted signal by analyzing the data collected from a short observation window to synchronize the local replica. The time period of the observation window is short compared to the PN code period. Determining the PN code phase is called PN acquisition.